1. Field of the Invention
The present invention relates generally to analysis of extracellular fluids that contain carrier proteins, and, more particularly, but not by way of limitation, to methods for prognosis and detection of toxemia in a patient by analyzing a serum sample from the patient.
2. Description of Related Art
For illustration, but without limiting the scope of the invention, the background is described with respect to analyzing the blood of a human patient.
In the early stages of toxemia, the ability of a patient's body to evacuate toxins from the blood stream may become compromised. That is, the patient's biological systems for evacuating toxins from the patient's blood stream may stop functioning properly and begin to permit toxins to build in the patient's body. In later stages of toxemia, these toxins generally reach relatively high levels (as compared to normal, toxin levels in a healthy patient), and the toxins may begin to cause noticeable symptoms such as illness, cell damage, organ failure, and the like. Currently known methods of diagnosing toxemia may not permit recognition or diagnosis of toxemia until later stages when symptoms are already noticeable. In these later stages, treatment may be less effective and may not be effective enough to prevent the death of the patient.
Analyzing hematologic parameters and/or measuring the concentration of various metabolites in blood samples from a patient are known in the art and may be widely-used methods of diagnosing toxemia (which may also be known in the art as toxaemia) in a patient, such as, for example, in a clinical setting. However, these known methods suffer a number of shortcomings and/or drawbacks.
One example of a known method may be referred to in the art as the “mean mass molecules” evaluation of a sample of a patient's blood serum. However, in the “mean mass molecules” evaluation, generally only a fraction of unbound, free endogenous toxins in the serum may be detected. This fraction may also be limited in that it may contain mostly toxins that are hydrophilic. “Absorbed” or “bound” hydrophobic toxins, which are respectively adsorbed on biological membranes or bound on carrier proteins, may not be detected. The failure to detect absorbed hydrophobic toxins can be detrimental to the treatment and recovery of the patient because these toxins may subsequently damage, or may have already damaged, cells, organs or systems in the patient. Such damage, caused by these absorbed and/or bound hydrophobic toxins, may subsequently cause changes in hematological parameters and/or other symptoms of toxemia.
Because the “mean mass molecules” evaluation (as well as other known methods of detecting toxemia) may not detect hydrophobic toxins, toxemia may not be detected until cells have been significantly damaged and/or hematologic changes or failures have already occurred. Stated otherwise, known methods of detecting toxemia may not detect toxemia in its early stages, and instead, may only detect toxemia in later stages of its development when it may be substantially harder to treat it effectively. In these later stages of toxemia, treatment may be inhibited by factors such as, for example, reduced capacity of the carrier proteins to evacuate toxins, and/or reduced capacity of the patients liver to detoxify or remove the toxins from the carrier proteins.
Soviet Union Patent, SU 1,459,656, published Feb. 23, 1989, describes a method of diagnosing endogenous toxemia by an evaluation of the ability of erythrocyte membranes to bind the fluorescent probe ANS. This method may permit detection of damage to erythrocyte membranes that has already occurred due to erythrocyte interaction with toxins (either hydrophilic or hydrophobic). This method may permit relatively-earlier detection of toxemia in a patient, such as, for example, at a stage in which toxins have already damaged cell membranes but before the damage is extensive enough to cause failure of organs and/or systems of the patient. Practically speaking, this method may permit detection of toxemia as much as approximately 6 to 12 hours before other hematological parameters show detectible changes or before other symptoms may appear. This method therefore still suffers from the shortcoming that it may not detect toxemia before toxins have damaged cells of the patient, and therefore may not permit treatment early enough during the development of the disease to prevent or minimize the effects, complications, or symptoms of toxemia.
U.S. Pat. No. 7,166,474 describes a method of detecting changes in transport properties of albumin by using electron paramagnetic resonance (EPR) spectroscopy (which may also be known in the art as electron spin resonance “ESR” spectroscopy) to evaluate a sample that contains albumin (an albumin-containing sample). This method can include evaluating the albumin transport function with respect to long chain fatty acids by using a spin probe represented by a spin-labeled fatty acid. Specifically, according to this method, the EPR-spectra of the spin probe can be measured in at least three aliquots of the sample, where each aliquot is mixed with significantly different concentrations of the spin probe and a high concentration of ethanol. The concentration of ethanol is high enough to induce significant conformational changes of the albumin to enable evaluation of the conformational flexibility of the albumin. The parameters of albumin transport function are derived from measurements of the conformational changes induced in the albumin artificially by the high ethanol concentration. This method assumes that albumin molecules efficiently release bound substances to target objects at conditions that occur in a healthy patient, and therefore induces a conformational change facilitating dissociation of albumin-bound ligands. While this may be useful in the method taught by this patent, the conformational changes induced by the high ethanol concentration prevents evaluation of the toxin-scavenging (toxin-binding) function of the albumin, because it assumes delivery of albumin-bound toxins to an excretion system, e.g. liver, rather than distribution of toxins throughout an organism in way similar to the delivery of nutrients to cells (permitting toxins to damage cells), as can happen in toxemic patients. This method suffers from possible shortcomings that may include, for example, the use of at least three aliquots of each sample, the fact that evaluation may be limited to certain albumin parameters, and excessive dissociation of bound substances (e.g., toxins) from the albumin (and/or from other serum proteins) resulting from the addition of relatively high-concentrations of ethanol. These possible shortcomings may contribute to variations in results and false-negatives in detecting the presence of protein-bound toxins in patients' blood.
A continuing need therefore exists for improved, faster, less-expensive, and/or more-accurate methods of detecting toxemia, especially in its early or precursor stages.